1. Field of the Invention
The present invention relates to a navigation system, user terminal, navigation device, and information recording method.
2. Description of Related Art
In a conventional navigation device, a current position of a vehicle is detected by means of GPS (global positioning system). At the same time, a vehicle direction is detected based on the vehicle's angular velocity detected by a gyro sensor. A map screen is formed on a display of a display section. A current position, a surrounding map, and the vehicle direction are indicated on the map screen. Therefore, an operator, can drive a vehicle following the current position, surrounding map and the vehicle direction indicated on the map screen.
If the driver sets a target destination and a search condition, a route from the current position up to the target destination is searched for based on the search condition. Then, the searched route is displayed on a search route display screen formed on the display or audibly output by an audio output section communicate. Therefore, the driver can drive a vehicle along the searched route.
The navigation device includes a communication section, and is capable of receiving traffic information, for example, congestion information through the communication section and displaying the received congestion information on the map screen.
A navigation system has been proposed in which the user transmits route guidance data to the navigation device before the user operates the vehicle. When the user operates the vehicle and starts driving, the route guidance can start following the transmission of the route guidance data (see Japanese Patent Application Laid-Open No. HEI 6-243395). In this case, the route guidance data is obtained by operating a personal computer at a home or in an office to input, for example, a target destination and/or search condition and route guidance data is transmitted to the navigation device while the vehicle is parked.
However, according to this conventional navigation device, if a time necessary for transmitting the route guidance data to the navigation device (hereinafter referred to as “required communication time”) is long, the navigation device needs to be turned on during that period. Therefore, electric power consumed by the navigation device is increased and a load applied to a battery mounted on the vehicle is increased tremendously.